Chain Reaction is a Radio 4 chat show in which the big names from the world of comedy and beyond pick a guest they would like to interview. In the following show, the interviewee then gets to become the host and picks a new guest to talk to.

This show is based on a format first used by a short-lived four-part series of the same name which aired over the 1991/1992 New Year period on the now defunct BBC Radio 5. This original series had no comic intentions but John Cleese did appear as the first guest.